1. Field of the Invention
The present invention generally relates to a method for modifying the surface of conventional commodity polymers, including without limitation polyurethanes, polyesters, polyethers, polyamides, polyimides, etc.
2. Background
Surface modification of a polymeric article is performed or attempted for a number of different reasons. For example, it may be desirable to have a bulk polymer that has a surface that is modified to better accept a paint or dye, or to have a surface that imparts a property such as resistance to chemical or radiant energy damage.
A number of different methods have been developed for modifying the surfaces of a polymer. Many of these methods involve post processing of the article. For example, the polymeric article may be exposed to a plasma, or a plasma processing step followed by grafting of compounds to the surface of the polymer. Also, the polymeric article might be subjected to a chemical or radiant energy exposure to alter the surface. It is known to combine a fluorinated polymer with a conventional polymer to get the surface-concentrated fluoropolymer. (Ji, Q.; Kang, H.; Wang, J.; Wang, S.; Glass, T. E.; McGrath, J. E., Surface characterization of fluorinated oxetane polyol modified polyurethane block copolymers, Polymer Preprints, 2000, 41, 346-347, Kim, Y. S.; Lee, J. S.; Ji, Q.; McGrath, J. E., Surface properties of fluorinated oxetane polyol modified polyurethane block copolymers, Polymer, 2002, 43, 7161-7170.) It is known that combining a fluorinated group with a UV absorbing chromophore surface-concentrates the chromophore. (Vogl, O.; Jaycox, G. D.; Hatada, K., Macromolecular design and architecture, Journal of Macromolecular Science-Chemistry, 1990, 27, 1781-1854.) It is known that combining a perfluorohexyl group with a fullerene surface-concentrates the fullerene at a styrene air interface. (Chen, W.; McCarthy, T. J., Adsorption/migration of a perfluorohexylated fullerene from the bulk to the polymer/air interface, Macromolecules, 1999, 32, 2342-2347.)
Certain work has occurred thus far on polymeric surface modifiers (PSM). Chen, W.; McCarthy, T. J., Macromolecules 1999, 32, 2342-2347; Ho, T.; Wynne, K; J. Polym. Adv. Tech. 1994, 6, 25-31; Ward, R. S.; White, K. A.; Hu, C. B., in Biomedical Engineering; Planck, H., Egbers, G., Syre, I., Eds.; Elsevier Science Publishers: Amsterdam, 1984.
Surfaces have been made hydrophobic using PDMS PSMs. Ho, Wynne, supra; Ratner, B. D., Yoon, S. C., Kaul, A., Rahman, R., in Polyurethanes in biomedical engineering II; Planck, H., Syre, I. Dauner, M., Egbers, G., Eds., Elsevier, New York, 1986; Vol. 3, pp. 213-229; Tezuka, Y., Fukushima, A., Matsui, S., Imai, K., Journal of Colloid and Interface Science, 1986, 114, 16-25. Surfaces have been made hydrophobic and oleophobic with fluorinated PSMs. Malik, A. A., Carlson, R. P., Aerojet General Corporation: US, 1997, p. 20; Thomas, R. R., Anton, D. R.; Graham, W. F., Darmon, M. J., Sauer, B. B., Stika, K. M., Swartzfager, D. G., Macromolecules 1997, 30, 2883-2890; Thomas, R. R., Ji, Q., Kim, Y. S., Lee, J. S., McGrath, J. E., Polyurethane 2000 Polymer Division Abstracts 2000; Thomas, R. R., Anton, D. R., Graham, W. F., Darmon, M. J., Stika, K. M., Macromolecules 1998, 31, 4595-4604. In this work, the modifying soft block usually consists of a single repeat as typified by polydimethylsiloxane PSMs where the repeat unit is [—(CH3)2SiO—] (see Ho, Wynne, supra) or surface modifiers derived from semifluorinated oxetane monomers that yield telechelics having a 3,3′ substituted 1,3-propylene oxide repeat, for example, [—CH2C(CH3)(CH2OCH2CF3)CH2O—] (see Kim, Y. S., Lee, J. S., Ji, Q., McGrath, J. E., Polymer 2002, 43, 7161-7170).
There has been work regarding oxetane monomers. Synthesis of fluorinated oxetanes is disclosed in U.S. Pat. No. 6,037,483 to Malik, et al. (“Polymers and prepolymers from mono-substituted fluorinated oxetane monomers”) and U.S. Pat. No. 5,807,977 to Malik et al. (“Solvent-free process for the preparation of mono-substituted fluorinated oxetane monomers”). There has been work regarding synthesis of polyurethanes containing fluorinated oxetanes (having a 3,3′ substituted 1,3-propylene oxide repeat). See Kim et al. (2002), supra.
Also mentioned as background are the following:
U.S. Pat. No. 6,479,623 to Malik, Archibald, Carlson, Wynne and Kresge, issued Nov. 12, 2002, titled “Amorphous Polyether Glycols based on bis-substituted oxetane copolymers.”
PCT Int. Application No. WO 2001-US44556 20011128, by Patel, Mohajer, Twomey, Mares and Nelson, Honeywell Int. Inc., “Polymeric additives and polymeric articles comprising the additive.”
PCT Int. Application No. WO1994-US5999, by Sastri, Mohajer, Young, Boyle, Allied Signal Inc., “Polydiorganosiloxane-modified polymer and its preparation.”